The present invention relates to a cleaning sheet which exhibits excellent cleaning performance on fluffy surfaces, particularly raised or piled surfaces, such as carpets, rugs, couches, and automotive seats.
JP-A-10-155713 discloses a disposable cleaning article comprising a base layer of a thermoplastic resin, a dust catching layer superposed on the base layer, and a cover layer of a thermoplastic resin having openings through which the dust catching layer is exposed. The dust catching layer is fabricated of a large number of continuous filaments of a thermoplastic resin. The cleaning article is designed to have a plurality of wiping functions so as to eliminate the trouble of using different cleaning articles according to the place to be cleaned. While the cleaning article is fit for cleaning a flat surface such as flooring but incapable of catching up hairs, etc. entangled with a carpet. Hairs, etc. cannot be caught up without applying a large force resistant to the friction. Thus, it is difficult for a cleaning article of this type to have both dust removing properties from a piled surface and operating properties in cleaning operation.
JP-A-2001-137169 discloses a fitting sheet which is removably fitted to a cleaning tool when a cleaning sheet is attached to the cleaning tool. The fitting sheet has been developed for saving the cleaning sheet by minimizing the area of the cleaning sheet to be attached to the cleaning tool and for using the cleaning tool clean. However, the cleaning sheet used in combination with the fitting sheet is spun-laced nonwoven and is incapable of scraping and catching up fibrous dust such as hairs entangled with a carpet.
JP-A-10-60761 proposes a cleaning sheet for collecting dust of small to large sizes, which comprises air-laid nonwoven fabric made of fibers having a fineness of 1.5 to 3 denier and air-laid nonwoven fabric made of fibers having a fineness of 6 to 32 denier, the two kinds of nonwoven fabric being arranged in an arbitrary configuration. This cleaning sheet is for cleaning smooth surfaces such as flooring and is not fit for cleaning piled surfaces such as a carpet.
JP-A-2000-110057 discloses a composite sheet for cleaning a piled surface such as a carpet which is prepared by entangling a web containing thermally shrinkable fiber with a net in three-dimensions and causing the web to shrink by heat treatment thereby to make the net project over the web surface. It is the projecting parts of the net that can enter into pile. Therefore, how deep the projections enter into pile depends on the configuration of the net, and the number of projections that can enter is limited. Considerably stiffer than pile, the projections can damage the pile. Since the net and the web are structurally integral with each other, it is difficult to control them separately. In order for allowing the net to project sufficiently, the fibers constituting the web should have limited freedom, which is unfavorable for making the web hold dust. That is, the sheet cannot be seen as satisfactory in ability to rake up dust and ability to hold the collected dust.
JP-A-9-21055 describes nonwoven composite fabric having short fibers oriented nearly randomly in the surface layer thereof. The nonwoven composite fabric has a controlled fiber composition and a controlled fiber orientation so as to have bulkiness and a satisfactory texture or feel. Therefore, the nonwoven composite fabric does not serve for cleaning a piled surface.
JP-A-10-262884 discloses a wiping sheet having a multilayer structure in which short fiber nonwoven fabric and a net of very thick fiber are superposed on each other. Having an unevenness on the surface, the wiping sheet exhibits both dust raking ability and dust holding ability. Accordingly, it is different in both idea and constitution from the present invention in which dust raking and dust holding are performed by a combination of sheets having the respective functions.
JP-A-2000-225084 proposes a cleaning tool for easily removing hairs, etc. entangled with a carpet which comprises a roller and a scraping sheet which has hooked projections and is wound around the roller. Because the number of the hooked projections that can be formed on the scraping sheet is limited, it is difficult to improve the cleaning performance to remove hairs, etc. Granting the number of the hooked projections could be increased, damage by the hooked projections to the surface to be cleaned would increase. That is, it is difficult to improve cleaning performance on hairs, etc. without increasing damage to the surface to be cleaned. In addition, it appears that the scraping sheet after collecting dust, such as hairs, is to be disposed of because of the difficulty in removing the collected dust from the sheet for reuse. Seeing that the scraping sheet has a complicated structure and is therefore costly, it is bad economy to dispose of the sheet after use.